FIG. 15 is a sectional view of a conventional pump (FIG. 2 of Patent Literature 1) used in a heat pump apparatus. This pump includes a stator part 17, a rotor part 21, a pump part 26, and a shaft 27. A lower end portion of the shaft 27 is fixed to a lower casing 15, and an upper end portion of the shaft 27 is fixed to a shaft support portion 35 of an upper casing 24, both in a non-rotatable manner. The rotor part 21 rotates freely around the shaft 27. The rotor part 21 includes a magnet part 20 at the outer circumference thereof, and a bearing 18 at the inner circumference, and the magnet part 20 and the bearing 18 are coupled together by a coupling member 19 made of a thermoplastic resin or the like. The coupling member 19 also forms a lower blade plate 25b. A plurality of blades 25c, arranged radially from the center in a circular arc or an involute curve, are placed between an upper blade plate 25a and the lower blade plate 25b, thereby forming an impeller 25. Rotation of the impeller 25 produces centrifugal force which acts on a liquid and causes the liquid to be pumped from a suction inlet 22 to a discharge outlet 23.
The shaft support portion 35 has the shape of a plurality of legs arranged in an inverted cone, and is configured to hold the positions of the shaft 27 and a thrust washer 28 which receives thrust force, and is fitted into a suction opening 36 of the upper blade plate 25a. 
The stator part 17 includes an iron core 10 formed of a plurality of stacked electromagnetic steel sheets, a winding 11 wound through a slot (not shown) of the iron core 10 via an insulator 12 (an insulating material), a circuit board 13 connected with a lead wire 14, and the lower casing 15 which is approximately pot-shaped. The circuit board 13 is positioned near one side of the stator part 17 opposite from the pump part. The rotor part 21 is housed in a hollow portion of the approximately pot-shaped lower casing 15. A shaft hole 15a into which the shaft is fitted is formed at a center portion of the hollow portion of the lower casing 15.